The present invention relates to a cell for sampling and storing fluid deposits.
These cells are closed receptacles with a calibrated volume in which are collected bottom samples of a pressurized fluid deposit or oil samples taken at the surface from the separator.
Such transfers of oil deposits are currently carried out in bottom sampling or in surface sampling using a mercury cell. After attaching a cell of this type, filled with mercury, onto the bottom sampling cell or onto the separator itself, the pressurized oil deposit is admitted into the mercury cell and a corresponding quantity of mercury is removed as it fills up.
Mercury is selected amongst all liquids because of its well-known intrinsic qualities of not polluting the transferred sample.
A technique of this type, widely known in the prior art and much employed, has disadvantages which are also caused by the nature of mercury. Firstly, mercury is a weighty product which makes the transfer operations heavier. Secondly, mercury is a dangerous product and highly toxic to such an extent that its use on a platform for the above application is forbidden by the terms of national statutory provisions such as, by way of example, the Norwegian regulations. In addition, if the sampled oil contains acid gases, H.sub.2 S for example, there are risks of a reaction which may considerably falsify the measurements of the sample, which measurements are mainly termed PVT (pressure volume temperature) measurements, such as measurement of the bubble point, pressure at which the bubble appears, gas-oil mass ratio, measurement of the retraction of the oil under the influence of the loss of gas, etc.